Machine tools of this kind in which the tools remain mounted in the magazine while being ready for use and while in actual use, have the advantage that tool changing equipment is not needed. A machine tool has already been proposed in which the magazine is capable of performing both rotary motions for transferring a selected tool into working position, and axial motions for feeding the tool (German Auslegeschrift No. 1 302 431). The motions in the longitudinal axis of the machine and particularly vertical motions which always involve considerable structural complications must then be associated with the workholder.
Another machine tool is already known in which vertical adjustment of a tool is effected by rotary motion of the magazine (German Offenlegungsshrift No. 2 038 842). This machine tool is designed for conventional machine jobs, particularly for drilling or milling. Several like rotary tool magazines may be disposed side-by-side and in this way the machine operations can be duplicated.
It is now the object of the present invention to provide a machine tool of the first herein specified kind which while involving little production expense is suitable for performing copy milling tasks. According to the invention, this is achieved by a guide drum or the like disposed alongside the magazine or magazines and endowed with the same degrees of freedom as the magazines with which it is adapted to be coupled in all directions of motion, besides carrying a tracer for tracing the profile or contour of a master or pattern. The tracer, attached to the guide drum, follows the profile or contour of a master or pattern and the compound motion consisting of translatory and rotary components is transmitted to the magazines containing the tools. These tools, therefore, move in the same way as the tracer so that the master or pattern is thus reproduced.
A structurally simple arrangement is one in which, according to the invention, the magazine and the guide drum are both mounted on a common slide which is traversible in the longitudinal direction of the machine.
The guide drum and the magazine can be coupled for common rotation in diverse ways, for instance according to one feature of the invention, mechanically by a chain drive or the like.
The proposed machine tool may also be equipped with a servo control, in which case, according to the invention, the slide and/or the guide drum is/are driven by servo means controlled by the tracer.
In another embodiment of the invention, the magazines and the guide drum are mechanically independently mounted, coupling being effected by means of an electrical, hydraulic or pneumatic transmission. The guide drum then functions principally as an element controlling the motions of the magazines.
It is also possible to copy at a larger or reduced scale if, according to yet another feature of the invention, the tracer is radially adjustable in the guide drum and the transmission means for the translatory motion of the guide drum to the magazine include a ratio which equals the ratio of the radii of the tracer and tool in relation to their axes of rotation. The reduction or enlargement in scale in the vertical due to the ratio of the two radii will thus be matched by a like reduction or enlargement in the other directions.
The invention also includes the possibility of controlling the guide drum in a conventional manner by a program, in which case all the motions of the guide drum will be transmitted to the magazine in the manner already described. Moreover, the magazine may be directly controlled by reference to a program by-passing the guide drum.